<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body style="height: 2000px;">
		<button id='backTop' style="position: fixed;">回到顶部</button>
		<script type="text/javascript">
			var backTop = document.getElementById('backTop');
			backTop.onclick = function (){
				window.scrollTo(0,100);
			}
		</script>
	</body>
</html>
